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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <h1>基础的get请求</h1>
    <form id="form" action="" method="">
        <input id="ipt" type="text">
        <button id="btn">输入学生id 查询他的详细信息</button>
    </form>
        
    <script>
        const oForm = document.getElementById('form')
        const oIpt = document.getElementById('ipt')
        const oBtn = document.getElementById('btn')

        oForm.onsubmit = function () {
            //1.实例化XMLHttpRequest 
            const xhr = new XMLHttpRequest();
            //2.打开路径
            xhr.open('get', '/user', true)
            //3.发送请求
            xhr.send()
            //4.监听事件
            xhr.onreadystatechange = function () {
                if (xhr.readyState === 4 && (xhr.status >= 200 && xhr.status <= 299)) {
                    console.log(xhr.responseText);
                }
            }
            return false;
        }
    </script>
</body>

</html>